Fetching and Parsing Email Messages

The IMAP protocol is a fairly finicky and complex beast, but the good news is that you don’t have to know much of it to search and fetch mail messages. imaplib-compliant examples are readily available online, and one of the more common operations you’ll want to do is search for messages. There are various ways that you can construct an IMAP query. An example of how you’d search for messages from a particular user is conn.search(None, '(FROM "me")'), where None is an optional parameter for the character set and '(FROM "me")' is a search command to find messages that you’ve sent yourself (Gmail recognizes “me” as the authenticated user). A command to search for messages containing “foo” in the subject would be '(SUBJECT "foo")', and there are many additional possibilities that you can read about in Section 6.4.4 of RFC 3501, which defines the IMAP specification. imaplib returns a search response as a tuple that consists of a status code and a string of space-separated message IDs wrapped in a list, such as ('OK', ['506 527 566']). You can parse out these ID values to fetch RFC 822-compliant mail messages, but alas, there’s additional work involved to parse the content of the mail messages into a usable form. Fortunately, with some minimal adaptation, we can reuse the code from Example 3-3, which used the email module to parse messages into a more readily usable form, to take care of the uninteresting email-parsing cruft that’s necessary to get usable text from each message. Example 7-12 illustrates.